The National Social Life, Health and Aging Project (NSHAP) is a longitudinal study of older adults designed to examine mechanisms by which social factors (e.g., intimate relationships, social networks) affect and are affected by health. I 2005-06, questionnaire and biomeasure data were collected from a nationally-representative sample of 3,005 community-dwelling adults 57-85 (W1). These referent respondents were reinterviewed in 2010-11, together with coresident spouses/partners (W2). We seek funding to reinterview all surviving referent respondents and W2 spouses/partners in 2015-16 (W3). This third wave will allow NSHAP investigators and the broader research community to: 1) test the overarching hypothesis that older adults with strong, functioning relationships have better health trajectories; 2) examine how those who experience a major social or health event from W1 to W2 respond in W3; 3) explore the extent to which health and social relationships are produced and maintained in a larger context (i.e., couple, household, family, community); and 4) estimate causal models of the effect of social relationships on health and vice versa. While NSHAP's W1 and W2 provide extensive health and social information, W3 will allow researchers to trace pathways of health and mortality for individuals and intimate partnerships within social context.